Update the ScriptInterpreterLua::LoadScriptingModule signature after the
TargetSP argument was added in #133290.

This patch improves the synchronization of the debugger's output and error
streams using two new abstractions: `LockableStreamFile` and
`LockedStreamFile`.

 - `LockableStreamFile` is a wrapper around a `StreamFile` and a mutex. Client
   cannot use the `StreamFile` without calling `Lock`, which returns a
   `LockedStreamFile`.

 - `LockedStreamFile` is an RAII object that locks the stream for the duration
   of its existence.  As long as you hold on to the returned object you are
   permitted to write to the stream. The destruction of the object
   automatically flush the output stream.

This makes GetOutputStreamSP and GetErrorStreamSP protected members of
Debugger. Users who want to print to the debugger's stream should use
GetAsyncOutputStreamSP and GetAsyncErrorStreamSP instead and the few
remaining stragglers have been migrated.

Remove Debugger::GetOutputStream and Debugger::GetErrorStream in
preparation for replacing both with a new variant that needs to be
locked and hence can't be handed out like we do right now.

The patch replaces most uses with GetAsyncOutputStream and
GetAsyncErrorStream respectively. There methods return new StreamSP
objects that automatically get flushed on destruction.

See #126630 for more details.

The Status constructor that takes an error has been removed in favor of
Status::FromError.

This patch removes all of the Set.* methods from Status.

This cleanup is part of a series of patches that make it harder use the
anti-pattern of keeping a long-lives Status object around and updating
it while dropping any errors it contains on the floor.

This patch is largely NFC, the more interesting next steps this enables
is to:
1. remove Status.Clear()
2. assert that Status::operator=() never overwrites an error
3. remove Status::operator=()

Note that step (2) will bring 90% of the benefits for users, and step
(3) will dramatically clean up the error handling code in various
places. In the end my goal is to convert all APIs that are of the form

`    ResultTy DoFoo(Status& error)
`
to

`    llvm::Expected<ResultTy> DoFoo()
`
How to read this patch?

The interesting changes are in Status.h and Status.cpp, all other
changes are mostly

` perl -pi -e 's/\.SetErrorString/ = Status::FromErrorString/g' $(git
grep -l SetErrorString lldb/source)
`
plus the occasional manual cleanup.

StreamFile subclasses Stream (from lldbUtility) and is backed by a File
(from lldbHost). It does not depend on anything from lldbCore or any of its
sibling libraries, so I think it makes sense for this to live in
lldbHost instead.

Differential Revision: https://reviews.llvm.org/D157460

This applies the same trick for Lua that I did for python in
27b6a4e63afe.

Differential Revision: https://reviews.llvm.org/D150624

FileSpec::GetFileNameExtension returns a StringRef. In some cases we
are calling it and then storing the result in a local. To prevent
cases where we store the StringRef, mutate the Filespec, and then try to
use the stored StringRef afterwards, I've audited the callsites and made
adjustments to mitigate: Either marking the FileSpec it comes from as
const (to avoid mutations) or by not storing the StringRef in a local if
it makes sense not to.

Differential Revision: https://reviews.llvm.org/D149671

These don't really need to be in ConstStrings. It's nice that comparing
ConstStrings is fast (just a pointer comparison) but the cost of
creating the ConstString usually already includes the cost of doing a
StringRef comparison anyway, so this is just extra work and extra memory
consumption for basically no benefit.

Differential Revision: https://reviews.llvm.org/D149300